The nine-yregnant women could improve the bone health of ear-old children of mothers who took vitamin D supplements during pregnancy had significantly larger bones and greater whole-body bone mineral concentrations than children of mothers who didn’t take vitamin D, said Cyrus Cooper, F.Med.Sci., of the Southampton General Hospital here, and colleagues.In a he longitudinal study of 198 children born to white mothers in 1991-1992 that was reported in the Jan. 7 issue of The Lancet, the researchers assessed the body build, nutrition, and vitamin D supplementation of the mothers during pregnancy. At about nine years after birth, the researchers used dual-energy x-ray absorptiometry to measure the children’s whole-body and lumbar spine bone-mineral content, bone area, and bone-mineral density. The study found that 49 of the mothers (31%) had insufficient levels of 25(OH)-vitamin D (11 to 20 µg/L) and 28 (18%) were vitamin D deficient (25(OH)-vitamin D less than 11 µg/L). Women who took vitamin D supplements or who were exposed to higher levels of sunshine during pregnancy were less likely to be deficient in vitamin D.Insufficient or deficient levels of 25(OH)-vitamin D during pregnancy were associated with reduced whole-body bone-mineral content in the nine-year old children (Pearson correlation coefficient=0.21; P=0.0088). Low 25(OH)-vitamin D in the mothers was also associated with reduced lumbar-spine bone mineral content in the nine-year olds (r=0.17; P=0.03). Only 30 women in the study (15%) took supplements containing vitamin D. The children of women who took vitamin D supplements had significantly greater whole-body bone mineral concentrations (r=0.42; P=0.0267) and greater bone areas (r=0.45; P=0.024). However, bone mineral density was not significantly associated with the mothers’ vitamin D supplement use P=0.16).Finally, the concentration of umbilical-venous calcium was also correlated with the children’s bone mineral concentrations at nine years old (r=0.22; P=0.0084). “Our study provides direct evidence that the intrauterine environment, as indicated by maternal vitamin D status during pregnancy, is significantly correlated with bone-mineral accrual at age nine years,” the authors said.“Vitamin D insufficiency was a frequent finding in this cohort of white women. However, vitamin D supplementation of such mothers, especially when the last trimester of pregnancy occurs during the winter months, could lead to an enhanced peak bone-mineral accrual and a reduced risk of fragility fracture in offspring during later life,” they concluded.

A randomized, controlled clinical trial should evaluate the effects of vitamin D supplements in pregnant women and their children, they added.